1. Field of the invention
The present invention relates, in general, to cooling fins. In particular, the invention relates to a bendable cooling fin which is stacked together in prescribed numbers and is used in the heat-exchanger of an air conditioning apparatus.
2. Description of the related art
A compact and high efficiency heat-exchanger has been long desired in an air conditioning apparatus. Such a heat-exchanger has heretofore used stacked cooling fins (hereinafter referred as a cooling fin block) through which a plurality of refrigerant flow pipes penetrate to exchange heat between refrigerant flowing through the refrigerant flow pipes and an external atmosphere through the cooling fin block. To accommodate the external shape of the air conditioning housing, the upper side of the cooling fin block is bent against the lower side thereof at a prescribed angle. In particular, such a heat-exchanger having a bent cooling fin block is used in a compact type air conditioner employed in an automobile, which has a relatively small mechanical compartment. Also, a heat-exchanger having a bent cooling fin block is used in a household air conditioner including an internal unit whose height is relatively small, as compared with its width.
Japanese laid-open patent (Kokai) 2-106228 discloses a method for manufacturing a heat-exchanger with a cooling fin block. The method disclosed in this laid-open patent includes four processes.
A first process is a preparation process in which a hole and a plurality of notches are formed in a thin plate (cooling fin) so that at least two connecting portions are left in the plate in the direction perpendicular to the longitudinal direction of the plate. A prescribed number of such plates are stacked one on top of another to make a cooling fin block.
A second process is a cutting process wherein the stacked plates (cooling fin block) are cut from one of the plurality of notches to the hole after the heat-exchanger is assembled by penetrating a plurality of refrigerant flow pipes through the cooling fin block.
A third process is a bending process in which the upper portion of the cooling fin block is bent at a prescribed angle.
A fourth process is a connecting process in which the refrigerant flow pipes at the upper and lower portions of the cooling fin block are connected with a connecting pipe.
In the above-described manufacturing method, four processes are required to make the heat-exchanger with a bent cooling fin block. In particular, in the cutting process, a keen blade is used to cut the connecting portion from one of the notches to the hole. It is necessary to adjust the direction of the blade so as to accurately aim at the hole. Thus, a practiced work is required when the cutting process is carried out.